/Engine/Plugins/Runtime/ChunkDownloader/Source/Public/ChunkDownloader.h
Download all pak files in the chunk, but don't mount. Callback is fired when all paks have finished caching (whether success or failure). Downloads will retry forever, but might fail due to space issues.
void DownloadChunk ( int32 ChunkId, const [FCallback](API\Plugins\ChunkDownloader\FChunkDownloader\FCallback) & Callback, int32 Priority )